It is well known that polyolefins deteriorate rather rapidly when exposed to ultraviolet light. Therefore, it is common practice to blend the polyolefins with a UV stabilizer in order to maintain their mechanical properties also under extended ultraviolet irradiation. These UV stabilizers are generally used in relatively small quantities; however, they are quite expensive and constitute a considerable portion of the price of the polyolefin composition. In addition to the high price, the usually employed ultraviolet stabilizers may have detrimental side effects on the mechanical properties of the polyolefin and may create odor and discoloration thereof.